Is it because of climate change? Scientists with the World Weather Attribution project concluded in a study released Friday that the likelihood of the heat wave currently baking Northern Europe is “more than two times higher today than if human activities had not altered climate.”

While attribution studies are not yet available for other record-heat episodes this year, scientists say there’s little doubt that the ratcheting up of global greenhouse gases makes heat waves more frequent and more intense.

Elena Manaenkova, deputy head of the World Meteorological Organization, said this year was “shaping up to be one of the hottest years on record” and that the extreme heat recorded so far was not surprising in light of climate change.

“This is not a future scenario,” she said. “It is happening now.”

What was it like to be in these really different places on these really hot days? We asked people. Here’s what we learned.

Ouargla, Algeria: 124°F on July 5

At 3 p.m. on the first Thursday of July, on the edge of the vast Sahara, the Algerian oil town of Ouargla recorded a high of 124 degrees Fahrenheit. Even for this hot country, it was a record, according to Algeria’s national meteorological service.

Abdelmalek Ibek Ag Sahli was at work in a petroleum plant on the outskirts of Ouargla that day. He and the rest of his crew had heard it would be hot. They had to be at work by 7 a.m., part of a regular 12-hour daily shift.

“We couldn’t keep up,” he recalled. “It was impossible to do the work. It was hell.”

By 11 a.m., he and his colleagues walked off the job.

But when they got back to the workers’ dorms, things weren’t much better. The power had gone out. There was no air conditioning, no fans. He dunked his blue cotton scarf in water, wrung it out, and wrapped it around his head. He drank water. He bathed 5 times. “At the end of the day I had a headache,” he said by phone. “I was tired.”

Ouargla’s older residents told him they’d never seen a day so hot.

Hong Kong: Over 91°F for 16 straight days

In this city of skyscrapers on the edge of the South China Sea, temperatures soared past 91 degrees Fahrenheit for 16 consecutive days in the second half of May.

Not since Hong Kong started keeping track in 1884 had a heat wave of that intensity lasted so long in May.

Swimming pools overflowed with people. Office air-conditioners purred. But from morning to night, some of the city’s most essential laborers went about their outdoor work, hauling goods, guarding construction sites, picking up trash.

One blistering morning, a 55-year-old woman named Lin gripped the hot metal handles of her handcart. She pushed it up a busy road, glancing over her shoulder for oncoming cars. She had fresh leafy greens to deliver to neighborhood restaurants in the morning, trash to haul in the evening. Some days, she had a headache. Other days, she vomited. EDITORS’ PICKS

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Poon Siu-sing, a 58 year-old trash collector, tossed garbage bags into a mounting pile. Sweat plastered the shirt onto his back. “I don’t feel anything,” he maintained. “I’m a robot used to the heat of the sun and rain.”